KR20180080920A - An apparatus for communication using unlicensed band and a method thereof - Google Patents

Abstract

An electronic device is disclosed. The electronic device includes a radio frequency (RF) module for receiving a signal from a base station of a first network through a downlink subframe including a plurality of symbols in an unlicensed band, and one processor set to operate in a first mode or a second mode to operate at lower power than the first mode. Accordingly, the present invention can more efficiently save signal reception power.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication method using a license-

The embodiments disclosed herein relate to techniques for receiving signals using a license-exempt band.

Carrier aggregation (CA) technology has been introduced in LTE (LTE-A) technology as one of the ways to broaden the bandwidth of mobile communication systems. In recent years, 3GPP has adopted licensed-assisted access (LAA) to set some carrier waves in the carrier frequency band for Wi-Fi in order to exceed the bandwidth limit due to the increase of mobile data traffic. Prior to the discussion on LAA, discussions are underway on LTE-U (unlicensed), a non-standard technology that uses Wi-Fi frequency bands as LTE frequency bands.

BSs supporting LAA or LTE-U may not occupy or occupy channels depending on channel conditions for transmission. An electronic device operating in the license-exempt band can detect the channel occupation state by detecting the reference signals of the base stations. Switching of the communication mode such as wakeup or sleep in the electronic device that grasped the channel state occupation is performed at the boundary of the symbol, slot or subframe. Therefore, the electronic device must maintain a transmission / reception state or a communication mode for a predetermined time regardless of whether the actual base station occupies the channel.

On the other hand, in a heterogeneous network using a license-exempt band such as WLAN, a channel may be occupied already. In this case, the electronic device should maintain operation with respect to the base station, even though signals are not expected to be transmitted from the LTE-U base station or the LAA base station.

According to the prior art, an electronic device may waste power unnecessarily to monitor or receive signals even when it is expected that there will be no transmissions from the LTE-U base station or the LAA base station.

The embodiments disclosed in this document can provide a communication method using the unlicensed band and an apparatus thereof to solve the above-mentioned problems.

An electronic device according to an embodiment disclosed in this document includes a radio frequency (RF) module for receiving a signal from a base station of a first network through a downlink subframe including a plurality of symbols in a license-exempt band, Mode or a second mode of operation that operates at a lower power than the first mode.

Also, a method according to an embodiment disclosed herein may include the steps of: measuring an intensity of a received signal in a first interval in which an electronic device in a wake up mode corresponds to a portion of a particular symbol; And switching to a sleep mode in a second interval including the remaining part of the specific symbol if the signal strength satisfies a specified level.

An electronic device according to another embodiment disclosed in this document includes a radio frequency (RF) module for performing communication with a first base station that performs a first network communication in a license-exempt band, When detecting a preamble transmitted through a specific frame from a second base station performing a second network communication in a first interval, information on a transmission time transmitted through the specific frame is obtained, And determine at least one processor to operate in a sleep mode based on information on the first network and to perform communication with the first network in a sleep mode during the second period .

According to various embodiments disclosed herein, an electronic device can more efficiently reduce signal reception power.

In addition, various effects can be provided that are directly or indirectly understood through this document.

1 illustrates a network environment to which the present invention may be applied.
2 is a diagram for explaining a listen-before-talk (LBT) operation in a base station.
Figure 3 illustrates a pattern of reference signals that may be applied to various embodiments of the present invention.
4 is a diagram for explaining the relationship between received signal strength and electronic device operation.
5 is a block diagram showing a configuration of an electronic device according to an embodiment of the present invention.
6 is a block diagram illustrating a functional configuration of a cellular module according to an embodiment of the present invention.
7 is a flowchart of a receiving operation of an electronic device in a license-exempt band according to an embodiment of the present invention.
8 shows a state of a cellular module of an electronic device according to an embodiment of the present invention.
Fig. 9 shows another example of the state transition operation of the cellular module of the electronic device according to the embodiment of the present invention.
10 shows another example of the state transition operation of the cellular module of the electronic device according to the embodiment of the present invention.
11 shows another example of the state transition operation of the cellular module of the electronic device according to the embodiment of the present invention.
12 is a block diagram showing a configuration of an electronic device according to another embodiment of the present invention.
13 is a block diagram illustrating an example of a functional configuration of a cellular module according to another embodiment of the present invention.
FIG. 14 is a block diagram illustrating a functional configuration of a cellular module and a Wi-Fi module according to another embodiment of the present invention.
15 is a block diagram showing the configuration of an electronic device according to another embodiment of the present invention.
16 shows a frame structure in a WLAN system.
17 shows the structure of a preamble and a signal in a WLAN system.
18 shows the structure of a signal field in a WLAN system.
19 shows a transmission waveform of a WLAN frame.
20 is a flowchart showing an example of the reception operation of the electronic device in the license-exemption band according to another embodiment of the present invention.
21 is a flowchart showing another example of the reception operation of the electronic device in the license-exemption band according to another embodiment of the present invention.
22 shows an example of state transition operation of the cellular module of the electronic device according to another embodiment of the present invention.

Various embodiments of the invention will now be described with reference to the accompanying drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes various modifications, equivalents, and / or alternatives of the embodiments of the invention. In connection with the description of the drawings, like reference numerals may be used for similar components.

In this document, the expressions "have," "may," "include," or "include" may be used to denote the presence of a feature (eg, a numerical value, a function, Quot ;, and does not exclude the presence of additional features.

In this document, the expressions "A or B," "at least one of A and / or B," or "one or more of A and / or B," etc. may include all possible combinations of the listed items . For example, "A or B," "at least one of A and B," or "at least one of A or B" includes (1) at least one A, (2) Or (3) at least one A and at least one B all together.

The expressions " first, " " second, " " first, " or " second ", etc. used in this document may describe various components, It is used to distinguish the components and does not limit the components. For example, the first user equipment and the second user equipment may represent different user equipment, regardless of order or importance. For example, without departing from the scope of the rights described in this document, the first component may be named as the second component, and similarly the second component may be named as the first component.

(Or functionally or communicatively) coupled with / to "another component (eg, a second component), or a component (eg, a second component) Quot; connected to ", it is to be understood that any such element may be directly connected to the other element or may be connected through another element (e.g., a third element). On the other hand, when it is mentioned that a component (e.g., a first component) is " directly connected " or " directly connected " to another component (e.g., a second component) It can be understood that there is no other component (e.g., a third component) between other components.

As used herein, the phrase " configured to " (or set) to be " adapted to, " To be designed to, "" adapted to, "" made to, "or" capable of ". The term " configured (or set) to " may not necessarily mean " specifically designed to " Instead, in some situations, the expression " configured to " may mean that the device can " do " with other devices or components. For example, a processor configured (or configured) to perform the phrases " A, B, and C " may be a processor dedicated to performing the operation (e.g., an embedded processor), or one or more software programs To a generic-purpose processor (e.g., a CPU or an application processor) that can perform the corresponding operations.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the other embodiments. The singular expressions may include plural expressions unless the context clearly dictates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art. The general predefined terms used in this document may be interpreted in the same or similar sense as the contextual meanings of the related art and are intended to mean either ideally or in an excessively formal sense It is not interpreted. In some cases, even the terms defined in this document can not be construed as excluding the embodiments of this document.

An electronic device in accordance with various embodiments of the present document may be, for example, a smartphone, a tablet personal computer, a mobile phone, a video phone, an e-book reader, Such as a desktop PC, a laptop PC, a netbook computer, a workstation, a server, a personal digital assistant (PDA), a portable multimedia player (PMP) A camera, or a wearable device. According to various embodiments, the wearable device may be of the type of accessory (e.g., a watch, a ring, a bracelet, a bracelet, a necklace, a pair of glasses, a contact lens or a head-mounted-device (HMD) (E. G., Electronic apparel), a body attachment type (e. G., A skin pad or tattoo), or a bioimplantable type (e.g., implantable circuit).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronic apparatus according to various embodiments will now be described with reference to the accompanying drawings. In this document, the term user may refer to a person using an electronic device or a device using an electronic device (e.g., an artificial intelligence electronic device).

1 shows a network environment that can be applied to the present invention.

Referring to FIG. 1, the electronic device 102 is capable of transmitting and receiving signals at the base station 110 and the license band. The electronic device 102 is capable of transmitting and receiving signals in the license-exempt band with the base station 120. In one embodiment, the electronic device 102 may only receive signals from the base station 120 in the license-exempt band. The electronic device 102 may support a set of carriers. The license band may be set in P-cells among a plurality of carriers. The license-exempt band can be set in the S-cell.

The network formed by the base stations 110 and 120 may be referred to as a first network. Base station 110 may send and receive signals in electronic device 102 and license bands. The base station 110 may be referred to as a base station, an evolved NodeB (eNB), or a base station (BS). The base station 120 can send and receive signals in the license-exempt band with the electronic device 104. [ The base station 120 may be referred to as a base station 110 or 120 as a base station, an evolved NodeB (eNB), a base station (BS), an LAA base station, or an LTE-U base station.

The AP 130 is a device that performs a role of connecting wireless devices to a wired device using a related standard such as Wi-Fi (e.g., IEEE 802.11). The AP may be referred to as a base station, a centralized controller, a Node B, or an evolved Node B (eNB). The network formed by the AP 130 may be referred to as a second network. The electronic device 104 may perform a second network communication via the AP 130. [

In one embodiment, the first network may be at least one of Long Term Evolution (LTE), LTE-A, LTE-U, or LTE LLA. The LTE related system is a part of E-UMTS (Evolved UMTS) using E-UTRA, adopting orthogonal frequency division multiple access (OFDMA) in the downlink and single carrier frequency division multiple access (SC-FDMA) It adopts.

In one embodiment, the second network may be a WLAN. The WLAN is based on the IEEE 802.11 standard and can be referred to as Wi-Fi (wireless fidelity).

Hereinafter, embodiments of the present invention will be described with reference to the base station 120 and the electronic device 102. [ The base station 120 may be a base station supporting an LTE LAA or LTE-U system.

In one embodiment, the LTE LAA or LTE-U system may utilize the resource structure of the LTE system. In a LTE system, a downlink subframe may consist of two consecutive slots in the time domain. The subframe i may be composed of a slot 2i and a slot 2i + 1. Hereinafter, the first slot of each subframe may be referred to as slot 0 (slot 0) and the second slot may be referred to as slot 1 (slot 1).

One slot may comprise a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain. For a normal cyclic prefix (CP), one slot may comprise 7 OFDM symbols. The LTE LAA operation may be performed for a subframe having a normal CP.

2 is a diagram for explaining an operation of performing an LBT (listen-before-talk) in the LLA base station 120. Referring to FIG.

The LLA base station 120 may perform the LBT before starting the downlink transmission in the license-exempt band. The LBT determines whether another transmission apparatus already occupies the channel before the LLA base station 120 starts transmission, and performs transmission when it determines that it is not occupied.

The LLA base station 120 may perform an operation of determining the state of a wireless channel as an LBT operation. This operation can be referred to as a clear channel assessment (CCA). In the present invention, CCA can be used in two ways. In one embodiment, the CCA may be based on an energy detect (ED) based CCA scheme that is based on the strength of the received signal. In this case, a received signal strength indicator (RSSI) may be used as an indicator of received signal strength. In another embodiment, the CCA may be a carrier sense (CS) based CCA. As an example of carrier sensing, there is a method of calculating the duration of a frame based on a length field in the preamble or a length field in the header. Hereinafter, the carrier sensing can be referred to as sensing.

In one embodiment, the LAA base station 120 performing the CCA may determine whether the state of the channel is idle or busy based on the strength of the received signal. If the LLA base station 120 performing the CCA satisfies the level of the received signal (e.g., when the received signal strength is less than or equal to the threshold value) for a predetermined period of time (e.g., 4 占 퐏) State. The LLA base station 120 may determine that the channel state is busy if the strength of the received signal does not satisfy the specified level for a predetermined time.

In one embodiment, the LLA base station 120 may perform the transmission if the particular channel is busy, but not if the channel is idle. The LLA base station 120 may perform a backoff operation to perform the transmission. The LLA base station 120 may set the counter N to a random value before starting transmission. The LLA base station 120 may decrease the counter by 1 if the channel is idle during the slot period T _sl . This process can be referred to as backprofessional. If the channel state is busy, the LLA base station 120 may freeze the counter and wait until the channel is idle again. The LLA base station 120 may start transmission at the moment the counter reaches zero.

The received signal strength can be measured during a predetermined time (CCATime) for determining the idle state. If the received signal strength is not maintained below the threshold for a predetermined time period, the LLA base station 120 may determine that the channel is busy. The LLA base station 120 may wait for a predetermined time T _d before performing the back off operation when the received signal strength is less than the threshold and the state is maintained for a predetermined time period. In FIG. 2, it is assumed that the counter is 5 before it is determined that the channel is busy. The LLA base station 120 may freeze the counter for a time period during which the channel is in a busy state and perform back-off again after the T _d time period. If the received signal strength is in the idle state after performing the backoff, the LLA base station 120 may decrease the counter to four after the slot interval, T _sl . When the received signal strength becomes equal to or greater than the threshold value in the state where the counter is 3, the LLA base station 120 may determine that the channel state is busy and maintain the counter during the busy state. If the received signal strength is again below the threshold, the LLA base station 120 may decrease the counter 3 to two. When the received signal strength is in the idle state at the counter 1, after the lapse of the slot period, T _sl , the LLA base station 120 decreases the counter to 0 and can perform transmission at the time when the counter becomes 0.

The moment the counter goes to zero may not coincide with the start time of the subframe or slot. In this case, the LLA base station 120 may transmit data at a subframe or slot start time without directly transmitting data. The LLA base station 120 can transmit a dummy signal, which is a meaningless signal, from the time when the counter becomes 0 to the next subframe or slot start time. In the present invention, subframes and / or slots may correspond to subframes and slots of an LTE system.

The LLA base station 120 may transmit a reference signal at a subframe or slot start time after transmitting the dummy signal. The reference signal can be used for signaling the start of transmission.

FIG. 3 shows an example of a pattern of a reference signal that can be applied to the present invention. A reference signal is a signal used for channel information acquisition or data demodulation. The types of reference signals include a cell-specific reference signal (CRS), a demodulation reference signal (DM-RS), a channel state information reference signal (CSI-RS) have.

The CRS may be transmitted in all downlink subframes in the cell supporting transmission of the physical downlink data channel. The CRS may be transmitted in one or more of antenna ports 0 through 3. CRS can be used for channel measurement and channel information acquisition.

FIG. 3 shows a CRS pattern defined for antenna port 0. For antenna port 0, the CRS may be mapped to a resource element on a subframe according to the CRS pattern. Referring to FIG. 3, the CRS pattern of antenna port 0 is denoted by R0. Accordingly, the CRS can be transmitted in the first and fifth symbols in slots 0 and 1, respectively.

Hereinafter, in some embodiments of the present invention, various methods are described based on the case where the base station 120 transmits a CRS at antenna 0, but a pattern of various reference signals can be applied to the signal detection method described in the present invention .

The electronic device 102 may blindly detect the reference signal to determine whether there is a signal transmitted from the LLA base station 120. [ The electronic device 102 may sense a channel to determine whether a reference signal is transmitted. If the electronic device 102 determines that there is a reference signal from the LLA base station 120, it may determine that there is a signal to be received and receive a signal from the LLA base station 120 during a subframe or slot period. If the electronic device 102 determines that there is no reference signal to be transmitted, the electronic device 102 determines that there is no signal to be received and can change the operation mode or the communication mode with the LLA base station 120.

The operation mode or the communication mode may be the first mode or the second mode. The first mode may be a wake-up mode. In the wakeup mode, the electronic device 102 is capable of communicating with the LLA base station 120. In the wakeup mode, the electronic device 102 may establish a wireless connection with the LLA base station 120. The second mode may be a low power mode of operation as compared to the wake-up mode. The second mode may be a sleep mode. The sleep mode may indicate a state of operation with lower power than the wake-up mode. The sleep mode can indicate that the unused module is powered off. The sleep mode may include the case where the module is at zero power. The sleep mode may include a case in which a signal is not received from the LAA base station 120. Hereinafter, in the present invention, the wakeup mode may be referred to as a first mode and the sleep mode may be referred to as a second mode.

The electronic device 102 may perform blind detection of a reference signal in a particular one of a plurality of symbols included in a subframe or slot. In one embodiment, the particular symbol may be the first symbol. In one embodiment, the reference signal may be a CRS. When the reference signal is transmitted in the first symbol (hereinafter, symbol 0) according to the blind detection operation, the electronic device 102 can determine that the channel is busy during symbol 0. Or the electronic device 102 may determine that the channel is busy if the signal reception strength in the channel for symbol 0 is greater than or equal to a threshold value. If there is a case where the channel becomes idle during symbol 0, the electronic device 102 may determine that no reference signal is transmitted in the corresponding symbol. In this case, the electronic device 102 may determine that transmission from the LAA base station 120 is not performed.

Referring to FIG. 4, the operation of the electronic device will be described in the case where a part of the symbol 0 is kept busy while the other part is idle. According to one embodiment, the electronic device 102 may maintain the operating mode for the entire duration of symbol 0 in the first mode. The electronic device 102 may switch the operational mode from the first mode to the second mode after the entire duration of symbol 0 has expired. The electronic device 102 that switched to the second mode may no longer receive a signal from the LAA base station 120. [ According to one embodiment, the electronic device 102 maintains the module for receiving the LTE signal in the first mode even during the idle period. As a result, the electronic device 102 may unnecessarily consume power.

In the present invention, it is proposed to change the operation mode to the second mode even if the symbol 0 is not terminated when the electronic device 102 becomes busy and idle for a certain period of the symbol 0. The electronic device 102 performs CCA and may determine that the CRS is not transmitted if it determines that the channel is idle. The electronic device 102 may switch the cellular module to the second mode at the time symbol 0 is not terminated.

5 is a block diagram showing a configuration of an electronic device according to an embodiment of the present invention.

Referring to FIG. 5, the electronic device 500 may include a processor 502 and a cellular module 504. The electronic device 500 may send and receive signals to and from the base station 510 via the cellular module 504.

The processor 502 may perform various operations in accordance with the present invention and may control the cellular module 504. In one embodiment, the processor 502 may switch the operating mode of the cellular module 504 if it is determined that the channel is idle. The processor 502 may operate the cellular module 504 in a first mode for a portion of a particular symbol and the cellular module 504 in a second mode for a portion of the duration of the particular symbol.

The processor 502 may include one or more of a central processing unit (CPU), an application processor (AP), or a communication processor (CP). The processor 502 may perform computations or data processing related to, for example, control and / or communication of at least one other component of the electronic device 500.

The processor 502 may, for example, operate an operating system or an application program to control a plurality of hardware or software components connected to the processor 502, and may perform various data processing and operations. The processor 502 may be implemented with, for example, a system on chip (SoC). Processor 502 may load or process instructions or data received from at least one of the other components (e.g., non-volatile memory) into volatile memory and store the various data in non-volatile memory have.

The cellular module 504 can send and receive signals with the base station 510 in the license-exempt band. The cellular module 504 may be the cellular module 501 of FIG. The cellular module 504 can send and receive signals with the base station 510 via cellular communication. The base station may be an LAA base station or an LTE-U base station.

According to one embodiment, the cellular module 504 may perform at least some of the functions that the processor 502 may provide. According to one embodiment, the cellular module 504 may include a communications processor (CP). For example, the cellular module 504 may switch the operating mode of the cellular module 504 if it is determined that the channel is idle. The cellular module 504 may operate in a first mode for a portion of a particular symbol and may operate in a second mode for a portion of the duration of the particular symbol.

The cellular module 504 can send and receive RF signals through separate RF modules. The RF module is capable of transmitting and receiving, for example, a communication signal (e.g., an RF signal). The RF module may include, for example, a transceiver, a power amplifier module (PAM), a frequency filter, a low noise amplifier (LNA), or an antenna.

6 is a block diagram showing a functional configuration of a cellular module.

Referring to FIG. 6, the cellular module 501 may include a license-exempt band CCA module 610, a CRS detection module 620, and / or a sleep trigger module 630.

The license-exempt band CCA module 610 is a module that performs the CCA for the license-exempt band. The license-exempt band CCA module 610 can measure the channel status for the license-exempt band. The license-exempt band CCA module 610 can measure the received signal strength for the license-exempt band. In one embodiment, the unlicensed band CCA module 610 may perform an energy detection based CCA.

In one embodiment, the CRS detection module 620 may determine whether the CRS is present in a particular symbol based on the measured channel state in the unlicensed band CCA module 610. [ The CRS detection module 620 can determine whether a CRS exists in a specific symbol based on the measured received signal strength. For example, the CRS detection module 620 may determine that the CRS is not present in a particular symbol if the measured received signal strength is below a threshold. The CRS detection module 620 may determine that the CRS exists in a specific symbol when the measured received signal strength is equal to or greater than a threshold value.

The sleep trigger module 630 may trigger the second mode before the symbol 0 is terminated. The sleep trigger module 630 may switch the operation mode from the first mode to the second mode. Here, the second mode may be a sleep mode. Symbol 0 may be divided into a partial interval operating in the first mode and a remaining interval operating in the second mode.

Some configuration of the cellular module 501 may be implemented by the processor 602.

7 is a flowchart of a receiving operation of an electronic device in a license-exempt band according to an embodiment of the present invention.

Referring to FIG. 7, at operation 701, the electronic device 500 may operate in a first mode. For example, the electronic device 500 may set the cellular module 504 to the first mode.

At operation 703 and operation 705, the electronic device 500 may perform the CCA based on the received signal. In one embodiment, the CCA may be an energy detection based CCA scheme. At operation 703, the electronic device 500 may measure the strength of the received signal. The electronic device 500 may measure the received signal for a predetermined time. At operation 705, the electronic device 500 may determine whether the channel is idle. In one embodiment, the electronic device 500 may determine that the channel is idle if the received signal remains below a threshold for a predetermined amount of time. Or the electronic device 500 may determine that the CRS is not transmitted. The electronic device 500 may determine that the channel is not idle if the received signal is not maintained below the threshold for a predetermined time. The channel state in this case can be referred to as busy state. If the channel state is busy, the electronic device 500 may perform an operation 705.

If the channel state is idle, the electronic device 500 may switch the operation mode from the first mode to the second mode. The electronic device 500 may switch the cellular module 504 to the second mode. In one embodiment, the electronic device 500 can drive the cellular module 504 with less power than the first mode. In one embodiment, the electronic device 500 may not receive a signal or receive a signal at a lower power than the first mode. The first mode may be a wakeup mode and the second mode may be a sleep mode.

The interval operating in the second mode may be determined based on whether or not the partial start subframe is supported. At operation 709, the electronic device 500 may determine whether it supports a partial start sub-frame. If the electronic device 500 supports a partial start sub-frame, then the electronic device 500 may perform an operation 713. The electronic device may operate in the second mode up to the next slot. If the electronic device 500 does not support a partial start sub-frame, the electronic device 500 may perform an operation 711. [ The electronic device may operate in a second mode up to the next sub-frame.

8 to 11 are diagrams for explaining the operation of the electronic device 500 or the cellular module 504 according to various situations. The operation of the electronic device 500 according to the LBT operation of the base station 510 and the data transmission operation based on the LBT will be described with reference to Figs. 8 to 11. Fig.

8 shows a state of a cellular module of an electronic device according to an embodiment of the present invention. The base station 510 can transmit a dummy signal when it determines that the channel is not occupied by another base station or the like according to the LBT operation. 8, the base station 510 may transmit the dummy signal from the time t ₀ of the counter is 0 and t _n is the start of the sub-frame n. The base station 510 may start transmission at the boundary of the subframe. The base station 510 may transmit the CRS and transmit data. The base station 510 may transmit CRS on any one of a plurality of symbols constituting a subframe. The base station 510 may transmit the CRS in symbol 0, which is the first symbol of a plurality of symbols. The base station 510 may transmit data on at least one symbol of the plurality of symbols except for the symbol 0.

Electronic device 500 includes the sub-frame at the beginning: there can set an operation mode (for example, time point t _n) in a first mode. In one embodiment, the electronic device 500 may set the mode of operation from the second mode to the first mode. In one embodiment, the electronic device 500 may set the cellular module 504 to the first mode. In FIG. 8, since the channel remains busy during symbol 0, the electronic device 500 may remain in the first mode state until symbol 0 is ended. In the case of FIG. 8, the electronic device 500 may not perform an early switching operation to the second mode in the middle of symbol 0.

Fig. 9 shows another example of the state transition operation of the cellular module of the electronic device according to the embodiment of the present invention.

Referring to FIG. 9, the base station 510 may determine that the channel is in a busy state in the symbol 0 of the subframe n, and perform a backoff. The base station 510 may keep the counter constant in the freeze state when the channel is busy and may resume the backoff if the channel is idle again. The base station 510 if it is determined that the channel is idle, it is possible to perform a back-off at the time t _b. The base station 510 may transmit the dummy signal from the time t ₀ of the counter is 0 and the start time of t _{n + 1} sub-frame n + 1. Base station 510 may begin transmission in subframe n + 1. The base station 510 may transmit the CRS and transmit data. The t _b- may be a time point located in the first symbol interval of the subframe.

The electronic device 500 may set the operation mode to the first mode at the sub-frame boundary t _n . In this case, the subframe may be a downlink subframe. The electronic device 500 may determine that the channel is in a busy state from t _n to t _b . The electronic device 500 may determine that the received signal strength measured at a specific point in time (e.g., t _b ) is below a threshold due to backoff of the base station. Here, the specific time may be a time point located in a first symbol interval of a subframe. The electronic device 500 may determine whether the received signal strength meets a specified level for a predetermined time.

In FIG. 9, because the received signal strength is below the threshold value for a predetermined time, the electronic device 500 can switch the operation mode from the first mode to the second mode. The predetermined time may be set to, for example, a CCAtime value. The predetermined time can be, for example, 4 mu s.

When the electronic device 500 determines that the channel is idle within the specific symbol 0, the electronic device 500 may operate in the second mode in a remaining interval except for a certain interval that operates in the first mode from the symbol 0. The partial section may correspond to the period t _b + CCAtime the elapsed time of the set time from the start time t _n of the sub-frame n. t _b + CCAtime may be a value less than t _n + 78 μs, which is the ending point of symbol 0. Here, 78 占 퐏 may correspond to the length of the OFDM symbol of the LTE system.

The electronic device 500 may keep the operation mode in the second mode until the subframe n is finished. The electronic device 500 changes the operation mode to the first mode and monitors the channel status at the time t _{n + 1} at which the subframe n + 1 starts. The electronic device 500 can measure the received signal strength from the time point t _{n + 1} .

The description of FIG. 9 may be that of electronic device 500 when electronic device 500 does not support a partial start sub-frame.

10 is a diagram for explaining the operation of the electronic device 500 when the electronic device 500 supports the partial start sub-frame. In the partial start sub-frame, the base station 510 can perform transmission on a slot-by-slot basis. The base station 510 can perform transmission in slot 1 even if it does not perform transmission in slot 0. Since the operation of the base station in slot 0 of FIG. 10 is the same as that of FIG. 9, duplicate description will be omitted.

Base station 510 may initiate transmission in slot 1. The base station 510 may start the transmission at the t _s the start of the slot. The base station 510 may transmit the CRS in a specific symbol among the symbols constituting the slot 1. [ Base station 510 may transmit CRS at symbol 0, which is the first symbol of slot 1, and transmit data at least one symbol of the remaining symbols.

Operation of the electronic device 500 in slot 0 is the same as operation in slot 0 of the electronic device 500 of FIG. 9, and redundant description will be omitted below. The electronic device 500 may keep the operating mode in the second mode for a portion of slot 0.

Electronic device 500 may change the operation mode at the time t _s of the slot 1 is started in a first mode to monitor the channel conditions. The electronic device 500 can measure the received signal strength from the time point t _s . The electronic device 500 may switch the cellular module 504 to the first mode and perform blind detection on the CRS. As an example, the electronic device 500 may switch the cellular module 504 to the first mode and perform the CCA. In FIG. 9, since the base station 510 transmits a CRS in slot 1, the electronic device 500 can detect the CRS and receive the signal transmitted from the base station 510.

11 shows the operation of the electronic device 500 when the base station 510 performs a backoff operation at the start of subframe n.

11, the base station 510 is a dummy signal from the time t ₀ to perform a backoff operation at the start of the sub-frame n, and the counter is zero to t _{n + 1} is the start of the sub-frame n + 1 Lt; / RTI > The base station can transmit signals from sub-frame n + 1. For example, the base station may transmit data after transmitting the CRS at symbol 0, which is the first symbol of subframe n + 1.

The electronic device 500 can set the operation mode to the first mode at the start time t _n of the subframe n. The electronic device 500 may perform the CCA from t _n . Base station 510 to back off from the t _n and because the electronic device 500 may determine that the signal receiving strength less than or equal to the threshold value. If the signal reception strength is maintained below a threshold value for a predetermined time, the electronic device 500 may switch the operation mode from the first mode to the second mode. In the case of FIG. 11, the time required from the start of the subframe to the switching of the operation mode is shorter in the electronic device 500 than in the case of FIG. 8 to FIG. For example, the electronic device 500 may switch the operation mode when a predetermined time has elapsed from the start of the subframe. In Fig. 11, the power saving effect of the electronic device can be maximized.

According to the embodiment of the present invention described above, the cellular module can switch from the first mode to the second mode during the symbol interval when the channel becomes idle in the symbol 0 interval. Accordingly, power consumption can be reduced as compared with the prior art in which the first mode must be maintained during the entire period of the symbol 0.

On the other hand, a channel may be occupied in a heterogeneous network or in a heterogeneous communication system independently of whether the base station performing cellular communication is occupied. Hereinafter, a heterogeneous network or heterogeneous communication system may be referred to as a second network. Even if the second network occupies the channel and thus it is predicted that the transmission of the base station will not be performed, the conventional electronic device may perform CCA for the channel, resulting in waste of power unnecessarily. The present invention proposes a method for an electronic device to detect and predict when a channel is used for a second network communication and to reduce the power consumed by the CCA. Hereinafter, the second network will be described based on the case of WLAN (e.g., Wi-Fi).

12 is a block diagram showing a configuration of an electronic device according to another embodiment of the present invention.

12, an electronic device 1200 may include a processor 1202 and / or a cellular module 1204. Except for the description of the processor 1202 and the cellular module 1204 described below, redundant portions may refer to the description of the processor 502 and the cellular module 504 in Fig.

The cellular module 1204 can perform cellular communication with the base station 1210 in the license-exempt band. The base station 1210 may be at least one of base stations supporting LTE, LTE-A or LTE-U. The base station 1210 may be a base station that performs the LAA. The cellular module 1204 may be coupled to a first network formed by the base station 1210. The cellular module 1204 may be referred to as a first network module.

In one embodiment, the cellular module 1204 may perform at least some of the functions of the processor 1202. Cellular module 1204 may perform an energy detection based CCA. The cellular module 1204 can detect signals from the second network in the license-exempt band. The cellular module 1204 may detect a reference signal or a preamble transmitted from the second network. The cellular module 1204 may detect a signal or a preamble transmitted through the AP 1220. The cellular module 1204 may include a Wi-Fi preamble detection filter that detects the preamble transmitted from the AP 1220.

The AP 1220 may form a second network that is a heterogeneous network with the first network.

13 is a block diagram illustrating an example of a functional configuration of a cellular module according to another embodiment of the present invention.

A filter for Wi-Fi detection can be added inside the cellular module 1205 to detect a signal in the cellular module 1205 from a cellular network (e.g., LTE) and a heterogeneous network (Wi-Fi). In one embodiment, a filter for Wi-Fi preamble detection may be added to the cellular module 1205.

13, the cellular module 1205 may include a signal detector 1310, a transmission time calculator 1320, an inter-RAT (radio access technology) network allocation vector (NAV) configuration module 1330 .

The signal detector 1310 can detect the signal of the second network in the first period. The signal of the second network may be a reference signal or a preamble. In one embodiment, the second network may be a WLAN (e.g., Wi-Fi). In one embodiment, the preamble may be a Wi-Fi preamble. The signal detection unit 1310 may include a Wi-Fi preamble detection filter.

The transmission time calculating unit 1320 can calculate the channel occupation time of the second network. The transmission time calculating unit 1320 may calculate a transmission time for performing transmission in the second network based on the reference signal or the preamble.

The inter-RAT NAV setting module 1330 can set the channel state to the busy state for the second period based on the calculated transmission time. The inter-RAT NAV setting module 1330 may switch the operation mode from the first mode to the second mode based on the calculated transmission time. In one embodiment, the inter-RAT NAV setting module 1330 may set the NAV to switch modes. The NAV may indicate time information indicating that the channel is in use. The inter-RAT NAV may be time information occupying the channel in the second network. In one embodiment, the first mode may be a wakeup mode for measuring channel conditions. In one embodiment, the second mode may be a sleep mode that does not measure channel conditions.

Some configuration of the cellular module 1205 may be implemented by the processor 1202.

FIG. 14 is a block diagram illustrating a functional configuration of a cellular module and a Wi-Fi module according to another embodiment of the present invention.

14, an electronic device 1400 may include a processor 1402, a cellular module 1404, and a Wi-Fi module 1406. [ In addition to the description of the processor 1402 and the cellular module 1404 described below, redundant portions may refer to the description of the processor 502 and the cellular module 504 in Fig.

The cellular module 1404 can perform cellular communication with the base station 1410 in the license-exempt band. The base station 1410 may be at least one of base stations supporting LTE, LTE-A or LTE-U. The base station 1410 may be a base station that performs the LAA. The cellular module 1404 may be coupled to a first network formed by the base station 1410. The cellular module 1404 may be referred to as a first network module. The cellular module 1404 may receive signals from the Wi-Fi module 1406.

Wi-Fi module 1406 can send and receive signals with AP 1420 in the license-exempt band. The Wi-Fi module 1404 may receive a reference signal or a preamble transmitted from the AP 1420. The Wi-Fi module 1406 may include a Wi-Fi preamble detection filter that detects a preamble transmitted from the AP 1420. The Wi-Fi module 1406 may forward the signal to the cellular module 1404 via the inter-module interface. The Wi-Fi module 1406 can transmit and receive RF signals through separate RF modules. Wi-Fi module 1406 may communicate with the second network. Wi-Fi module 1406 may be referred to as a second network module.

According to one embodiment, the Wi-Fi module 1406 may perform at least some of the functions that the processor 1402 may provide. According to one embodiment, the Wi-Fi module 1406 may include a communications processor (CP). Or some functionality of the Wi-Fi module 1406 may be provided by the processor 1402. [

The AP 1420 may form a second network, which is a heterogeneous network, with the first network. The second network may be a WLAN (e.g., Wi-Fi).

15 is a block diagram illustrating an example of a functional configuration of a cellular module and a Wi-Fi module according to another embodiment of the present invention.

Referring to FIG. 15, the Wi-Fi module 1407 may include a signal detection unit 1510. The cellular module 1405 may include a transmission time calculating section 1520 and / or an inter-RAT NAV setting module 1530.

The signal detection unit 1510 of the Wi-Fi module 1407 can detect a signal of the second network. The signal of the second network may be a reference signal or a preamble. In one embodiment, the second network may be a WLAN (e.g., Wi-Fi). In one embodiment, the preamble may be a Wi-Fi preamble. The signal detection unit 1510 may include a Wi-Fi preamble detection filter.

The Wi-Fi module 1407 may notify the cellular module 1405 that a reference signal or a preamble has been detected when the signal detection unit 1510 detects a reference signal or a preamble of the second network. Wi-Fi module 1407 may forward detected information to cellular module 1405 via an inter-module interface.

The transmission time calculating unit 1520 may receive the detection information transmitted through the inter-module interface. The transmission time calculating unit 1520 can calculate the channel occupancy time of the second network. The transmission time calculating unit 1520 may calculate a transmission time for performing transmission in the second network based on the reference signal or the preamble.

The inter-RAT NAV setting module 1530 can set the channel state to the busy state based on the calculated transmission time. The inter-RAT NAV setting module 1530 can switch the operation mode from the first mode to the second mode based on the calculated transmission time. The inter-RAT NAV setting module 1530 may set the NAV to switch modes. In one embodiment, the first mode may be a wakeup mode. In one embodiment, the second mode may be a sleep mode.

Some configuration of the cellular module 1405 may be implemented by the processor 1402. [

Hereinafter, a method of calculating the transmission time of the second network will be described with reference to FIGS.

16 shows a frame structure in the IEEE 802.11 WLAN system that can be applied to the present invention.

Referring to FIG. 16, the frame of the WLAN system may include an orthogonal frequency division multiplexing (OFDM) physical layer convergence procedure (PLCP) preamble, a signal field, and a data field. The frame of the WLAN system may be referred to as a PLCP protocol data unit (PPDU) frame.

The PLCP preamble can be used to detect the start of a signal and perform time / frequency synchronization with a module (e.g., cellular module 1405 or Wi-Fi module 1407) receiving the signal. Symbol < / RTI >

The signal field includes a rate field indicating a data rate of 4 bits in a PLCP header, a reserved field of 1 bit size, a length field of 12 bits, a parity field of 1 bit, And a tail field of < / RTI > The signal field may include one symbol. In one embodiment, one symbol may be an OFDM symbol.

The data field may include a 16-bit size service field of the PLCP header, a PLCP service data unit (PSDU), and a tail field. The data field may further comprise padding bits for matching the octet of the PPDU frame.

17 shows the structure of a PLCP preamble and a signal. Referring to FIG. 17, the preamble may be implemented with a length of 16 .mu.s. The preamble may include a short training field (STF) sequence in the first half of 8μs and a long training field (LTF) sequence in the second half of the 8μs. The STF sequence is used for signal detection and coarse synchronization, and the LTF sequence can be used for fine time / frequency synchronization.

The signal field can be implemented with a length of 4 μs. The signal field may include data rate and length information. A module (e.g., cellular module 1505, Wi-Fi module 1507) that receives the signal may detect the signal using a preamble and perform time / frequency synchronization. The module receiving the signal can receive the signal field and determine the transmission rate and length information used for data transmission. In one embodiment, the module receiving the signal can determine the transmission rate and length information used in the PSDU.

18 shows the structure of a signal field in a WLAN system.

Referring to FIG. 18, the rate field includes 4 bits of R1 to R4, and 4 bits of information may indicate a data rate used for transmission of a PSDU. The data rate is related to the data transmission rate. The length field is expressed in 12 bits and can indicate the length of the PSDU.

Table 1 shows the data rate expressed in 4 bits of the rate field in the 20 MHz bandwidth.

R1-R4 Rate (Mb / s)
(20MHz channel spacing) Rate (Mb / s)
(10MHz channel spacing) Rate (Mb / s)
(5MHz channel spacing) 1101 6 3 1.5 1111 9 4.5 2.25 0101 12 6 3 0111 18 9 4.5 1001 24 12 6 1011 36 18 9 0001 48 24 12 0011 54 27 13.5

The transmission time (txtime) of the WLAN frame can be calculated by Equation (1) using the data rate and length information of the signal field.

Each variable may be a value defined in the IEEE 802.11 standard. T _preamble is the length value of the preamble. The T _preamble can be 16 μs. T _signal is the length of the signal field, which can be 4 μs. T _SYM can represent the length of an OFDM symbol. T _SYM may be 4 μs. N _SYM represents the number of symbols used for data transmission. Therefore, the product of T _SYM and N _SYM can represent the transmission time of the data.

N _SYM can be defined by the following equation (2).

Ceiling is a ceiling function. Ceiling (x) defines the smallest integer greater than or equal to x. N _DBPS Represents the number of data bits per OFDM symbol. 16 + 8 x LENGTH + 6 represents the total number of bits used in the service field, PSDU, and tail field. 16 corresponds to the service bit of the data field. 8 x LENGTH corresponds to the PSDU bit. 6 corresponds to the tail of the data field. The value obtained by dividing the total number of bits by the number of data bits N _DBPS corresponds to the total number of OFDM symbols N _SYM .

N _DBPS can be determined according to the data rate used for data transmission. Table 2 below shows N _DBPS over rate.

Modulation Coding Rate (R) Coded bits per subcarrier (N _BPSC ) Coded bits per OFDM symbol (N _CBPS ) Data bits per OFDM symbol (N _DBPS ) Data rate (Mb / s) (20 MHz channel spacing) Data rate (Mb / s) (10 MHz channel spacing) Data rate (Mb / s) (5 MHz channel spacing) BPSK 1/2 One 48 24 6 3 1.5 BPSK 3/4 One 48 36 9 4.5 2.25 QPSK 1/2 2 96 48 12 6 3 QPSK 3/4 2 96 72 18 9 4.5 16-QAM 1/2 4 192 96 24 12 6 16-QAM 3/4 4 192 144 36 18 9 64-QAM 1/2 6 288 192 48 24 12 64-QAM 3/4 6 288 216 54 27 13.5

Referring to Table 2, for example, when the rate is 18 Mbps in the 20 MHz bandwidth, N _DBPS has 72 bits. If the rate is 6 Mbps, N _DBPS has 24 bits.

If the length is 1500 bytes and the rate is 6 Mbps, N _SYM may be 501 according to equation (2). In this case, the transmission time Txtime may be 2024 占 퐏.

On the other hand, an electronic device (e.g., 1200, 1400) may detect a signal transmitted over a WLAN frame based on the transmission waveform of the WLAN frame. The electronic device 1200, 1400 can detect the transmission waveform of the WLAN frame using a filter.

19 shows a transmission waveform of a WLAN frame.

The signal transmitted in the time domain has a waveform as shown in Fig. The first 8μs represents the transmission waveform of the STF sequence, the middle 8μs represents the transmission waveform of the LTF sequence, the signal field can then be transmitted for 4μs and the last data can be transmitted.

Hereinafter, an embodiment of the present invention will be described with reference to the electronic device 1200. FIG. The following embodiments may be performed in the electronic device 1400. [

20 is a flowchart showing an example of the reception operation of the electronic device in the license-exemption band according to another embodiment of the present invention. The operation of the electronic device 1200 according to the channel occupation state of the second network will be described with reference to Fig.

In operation 2001, the electronic device 1200 may sense whether a reference signal or a preamble is transmitted from a base station of the second network. For example, a base station (e.g., AP 1420) of the second network.

In operation 2003, the electronic device 1200 may determine whether a reference signal or a preamble has been detected. The electronic device 1200 can determine whether the reference signal or the preamble is detected using the signal detection unit 1310 of the cellular module. If no reference signal or preamble is detected, electronic device 1200 may perform operation 2001.

When the reference signal or the preamble is detected, the electronic device 1200 can calculate a transmission end point of the second network. The end of transmission can be referred to as t _END . t _END can be calculated by the transmission time calculating unit 1520 of the cellular module 1310. t _END can be calculated based on the description related to Figs.

At operation 2007, the electronic device 1200 may perform settings for the second network based on t _END . The electronic device 1200 may set an inter-RAT network allocation vector (inter-RAT network allocation vector). The NAV may indicate time information indicating that the channel is in use. The inter-RAT NAV may be time information occupying the channel in the second network. NAV can act as a timer.

At operation 2009, the electronic device 1200 may switch the operational mode to the second mode. The electronic device 1200 may maintain the operation mode for the second period in the second mode. The second section may include some or all of the sections from the NAV setting point to t _END . The second section may include a part or all of the section from the NAV setting point to the end point of the PPDU frame. The second section may include some or all of the data fields of the PPDU frame. The second section may _end at t _END .

 21 is a flowchart showing another example of the reception operation of the electronic device in the license-exemption band according to another embodiment of the present invention. 21 illustrates the operation of the electronic device 1200 when the second network is a WLAN.

In operation 2101, the electronic device 1200 may sense whether a preamble is transmitted from the AP 1220.

At operation 2103, the electronic device 1200 may determine whether a preamble has been detected. Electronic device 1200 may determine if a preamble has been detected. The electronic device 1200 can determine whether a preamble has been detected using the receive filter. If no preamble is detected, the electronic device 1200 may perform an operation 2101. In the case of the electronic device 1400, the signal detection unit 1510 of the Wi-Fi module 1407 can detect the preamble.

If the preamble is detected, at operation 2105, the electronic device 1200 may calculate a transmission end point of the AP 1220 based on a signal field. The end of transmission can be referred to as t _END . t _END can be calculated by the transmission time calculating unit 1320 of the cellular module 1205. t _END can be calculated based on the description related to Figs. In the case of the electronic device 1400, the detection information may be transmitted from the signal detection unit 1510 of the Wi-Fi module 1407 to the transmission time calculation unit 1520 of the cellular module 1405. The detection information may include at least one of information indicating that a preamble has been detected, data rate and length information acquired in the PDCP frame, a preamble, a signal field, and a data field.

At operation 2107, the electronic device 1200 may perform settings for the second network based on t _END . The electronic device 1200 may set an inter-RAT NAV for the WLAN.

In operation 2109, the electronic device 1200 may switch the operation mode to the second mode. The electronic device 1200 may maintain the cellular module 1205 in the second mode until t _END . The electronic device 1200 may maintain the operation mode in the first mode during the first interval and may set the operation mode in the second interval to the second mode when the inter-RAT NAV is set. The second section may be maintained until t _END . The setting of the inter-RAT NAV can be maintained until t _END .

22 shows an example of state transition operation of the cellular module of the electronic device according to another embodiment of the present invention.

Referring to FIG. 22, the AP 1200 may start transmission at t _w . AP 1220 may transmit the preamble during t _{w -} t _w + 16μs and the signal field during t _w + 16μs for t _w + 20μs. Data is assumed to be transmitted during the interval from t _w + txtime t _w + 20μs. In one embodiment, txtime may be determined based on information transmitted over the PPDU frame. In one embodiment, txtime may be determined according to the description of Figures 16-18.

The electronic device 1200 may receive a preamble and a signal field over a PPDU frame. In this case, the operation mode may be the first mode. The electronic device 1200 may calculate the transmission time of the AP 1220 based on the preamble and the signal field.

The electronic device 1200 may calculate the transfer time and switch the operation mode from the first mode to the second mode. The electronic device 1200 may switch the cellular module 1204 to the second mode. The electronic device 1200 may operate in a first mode during a first interval and may operate in a second mode in a second interval. The first section may include a section corresponding to the preamble and the signal field. The second section may be determined based on the calculated transmission time. The second section may include a section corresponding to the data field. The length of the second section may correspond to the difference between the calculated transmission time and the length of the preamble and the signal field. Electronic device 1200 can maintain a second mode during the period from t _w + _w + 20μs txtime of Figure 22 t.

If the length field indicates 1500 bytes and the rate field indicates 6 Mbps, txtime may be 2024 microseconds. According to the prior art, the electronic device can keep the operating mode in the first mode for t _w + 2024 μs at t _w μs. On the other hand, according to the invention the electronic device 1200 in t _w t _w + μs only for 20μs is maintained when the first mode. That is, the period of keeping the operation mode in the first mode is 1% as compared with the conventional technology. Therefore, according to the present invention, unnecessary power consumption can be reduced by 99%.

Each of the components described in this document may be composed of one or more components, and the name of the component may be changed according to the type of the electronic device. In various embodiments, the electronic device may comprise at least one of the components described herein, some components may be omitted, or may further include additional other components. In addition, some of the components of the electronic device according to various embodiments may be combined into one entity, so that the functions of the components before being combined can be performed in the same manner.

As used in this document, the term " module " may refer to a unit comprising, for example, one or a combination of two or more of hardware, software or firmware. A " module " may be interchangeably used with terms such as, for example, unit, logic, logical block, component, or circuit. A " module " may be a minimum unit or a portion of an integrally constructed component. A " module " may be a minimum unit or a portion thereof that performs one or more functions. &Quot; Modules " may be implemented either mechanically or electronically. For example, a "module" may be an application-specific integrated circuit (ASIC) chip, field-programmable gate arrays (FPGAs) or programmable-logic devices And may include at least one.

At least a portion of a device (e.g., modules or functions thereof) or a method (e.g., operations) according to various embodiments may include, for example, computer-readable storage media in the form of program modules, As shown in FIG. When the instruction is executed by a processor (e.g., processor 502), the one or more processors may perform a function corresponding to the instruction. The computer readable storage medium may be, for example, a memory.

The computer-readable recording medium may be a hard disk, a floppy disk, a magnetic media such as a magnetic tape, an optical media such as a CD-ROM, a DVD (Digital Versatile Disc) May include magneto-optical media (e.g., a floppy disk), a hardware device (e.g., ROM, RAM, or flash memory, etc.) Etc. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the various embodiments. And vice versa.

Modules or program modules according to various embodiments may include at least one or more of the elements described above, some of which may be omitted, or may further include additional other elements. Operations performed by modules, program modules, or other components in accordance with various embodiments may be performed in a sequential, parallel, iterative, or heuristic manner. Also, some operations may be performed in a different order, omitted, or other operations may be added.

And the embodiments disclosed in this document are provided for the explanation and understanding of the disclosed technical contents, and do not limit the scope of the present invention. Accordingly, the scope of this document should be interpreted to include all modifications based on the technical idea of the present invention or various other embodiments.

Claims (20)

In an electronic device,
An RF (radio frequency) module for receiving a signal from a base station of the first network through a downlink subframe including a plurality of symbols in a license-exempt band, and
Wherein the at least one processor is configured to operate in a first mode or a second mode operating at a lower power than the first mode,
Measuring a strength of a received signal in the first mode in a first interval corresponding to a part of a specific symbol among the plurality of symbols,
And to operate in the second mode in a second interval including the remaining portion of the particular symbol if the measured signal strength meets a specified level. The method according to claim 1,
And the second interval is set to include the remaining symbols after the particular symbol among the plurality of symbols. The method according to claim 1,
Wherein the one subframe includes a plurality of slots, one slot of the plurality of slots includes the specific symbol,
And the second interval is set to include remaining symbols after the specific symbol among a plurality of symbols included in the one slot. The method according to claim 1,
Wherein the first mode is a wake up mode and the second mode is a sleep mode. The method according to claim 1,
Wherein the base station is a base station supporting long term evolution (LTE) licensed assisted access (LAA) or LTE-unicensed (LTE-U). The method according to claim 1,
Wherein the particular symbol is a first one of the plurality of symbols. The method according to claim 1,
Wherein the downlink subframe includes a plurality of slots,
Wherein the specific symbol is a first one of symbols included in one of the plurality of slots. The method according to claim 1,
Wherein the at least one processor is configured to define the specified level when the measured strength of the received signal is less than a threshold for a predetermined time. The method according to claim 1,
Wherein the at least one processor is configured to express the strength of the measured received signal as a received signal strength indicator (RSSI). The method according to claim 1,
Wherein the at least one processor is configured to operate in the first mode after the second period. The method of claim 7,
And the downlink subframe is a partial start subframe. A method for an electronic device in a wireless communication system to receive a signal in a license-
Measuring an intensity of a received signal in a first interval in which an electronic device in a wake up mode corresponds to a portion of a specific symbol, and
And switching to a sleep mode in a second interval including a remaining portion of the specific symbol if the measured strength of the received signal satisfies a specified level. The method of claim 12,
Wherein the specific symbol is a first one of a plurality of symbols included in a downlink subframe. The method of claim 12,
Wherein the specific symbol is a first one of a plurality of symbols included in a slot of a plurality of slots included in a downlink subframe. The method of claim 12,
And switching to the first mode after the second period. An electronic device,
A radio frequency (RF) module for communicating with a first base station for performing a first network communication in a license-exempt band, and
And at least one processor electrically coupled to the RF module,
When detecting a preamble transmitted through a specific frame from a second base station performing a second network communication in a first interval, acquires information on a transmission time transmitted through the specific frame,
Determining a second interval for operating in a sleep mode based on the information about the transmission time,
And communicate with the first network during the second interval in a sleep mode. 18. The method of claim 16,
Wherein the specific frame is a PLCP protocol data unit (PPDU) frame. 18. The method of claim 16,
Wherein the at least one processor is configured to obtain information about the transmission time via a physical layer convergence procedure (PLCP) header. 18. The method of claim 16,
Wherein the at least one processor is configured to determine the second section based on a rate field and a length field transmitted over the particular frame. 18. The method of claim 16,
The first base station is a base station supporting long term evolution (LTE) licensed assisted access (LAA) or LTE-unicensed (LTE-U)
And the second base station is a base station supporting a wireless local area network (WLAN).

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